1. Field of the Invention
This invention relates to the compound 7-ethyl-undeca-2,4-dione.
2. Description of the Prior Art
Considerable attention of recent has been directed to the commercial refining of transition base metals by the liquid-liquid extraction method. In accordance with this method, a water-immiscible organic solvent containing an organic extractant or chelating agent is intimately contacted with a dilute metal-bearing aqueous leach solution whereupon the two phases are permitted to separate. After separation from the metal-depleted aqueous solution or raffinate, the metal-loaded organic phase is contacted with an aqueous solution of a strong acid in a stripping operation to effect the transfer of the metal values from the organic phase back to an aqueous phase to provide a suitably concentrated solution thereof for subsequent recovery by electrolysis. The stripped organic phase is recycled to treat a fresh aqueous feed solution whereas the raffinate is recycled to the leaching operation.
The extractant reagents most commonly in use at the present time for this purpose are either the substituted oxine or hydroxy oxime type. These reagents find principal use in the recovery of copper from acid leach solutions thereof in which type of system they have proven to be very effective. Although these reagents can be used to extract metals from ammoniacal leach solutions, a problem arises in so doing which is not encountered in the refining of acid solutions. Briefly stated, the problem is that both of the indicated extractants, because of their related chemical nature, commonly promote an intolerable degree of ammonia carryover from the extraction stage to the stripping stage and similarly result in almost a mole for mole carryover of acid from the stripping stage to the extraction stage. The net result of these carryovers beyond involving the costly wasteful consumption of ammonia, is that ammonium sulfate forms and builds up to a point whereby the efficiency of the operation is seriously impeded. It is accordingly the object of this invention to provide a chelation reagent which obviates the foregoing problem associated with the use of the substituted oxine or hydroxy oxime type reagents.